Power conversion device

ABSTRACT

Disclosed is a power conversion device comprising: a case; a switching unit comprising a plurality of switches which are disposed on one side of the case; a transformer disposed on one side of the case; and a clip for fixing the plurality of switches. The clip comprises: a body part which is fixed to the case; and elastic parts which extend from the body part and are for pressing the plurality of switches to the case. The body part comprises a plurality of first through holes into which screws are coupled. And the first through holes are disposed between two adjacent elastic parts.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of U.S. patentapplication Ser. No. 16/067,029 filed Jun. 28, 2018, which is a U.S.National Stage Application under 35 U.S.C. § 371 of PCT Application No.PCT/KR2017/000177, filed Jan. 6, 2017, which claims priority to KoreanPatent Application No. 10-2016-0002683, filed Jan. 8, 2016, whose entiredisclosures are hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to a power conversion device.

BACKGROUND ART

Hybrid vehicles that use a motor include a motor control unit forcontrolling the motor and a direct current (DC)-DC converter.

The DC-DC converter that is a device for converting power, can convert aDC into an alternating current (AC), can transform and then rectify thecurrent, and can output a DC. In this procedure, a large amount of heatis generated in the DC-DC converter. Thus, a cooling system is providedto eliminate heat from the DC-DC converter. The cooling system can bedisposed at a lower portion of a case and can absorb heat generated incomponents of the cooling system.

In this case, when a contact between electronic components and the caseis non-uniform, cooling efficiency may be lowered. In particular, whenareas in which a plurality of switches for switching voltages, forexample, metal oxide semiconductor field effect transistors (MOSFETs)contact the case, are different from one another, cooling efficiency ofeach of the plurality of switches is changed so that performance of theDC-DC converter may be deteriorated.

DISCLOSURE Technical Problem

The present invention is directed to providing a power conversion devicein which a plurality of switches can be fixed to a case using an uniformpressure.

Technical Solution

One aspect of the present invention provides a power conversion deviceincluding: a case; a switching unit including a plurality of switcheswhich are disposed on one surface of the case; a transformer disposed onone surface of the case; and a clip for fixing the plurality ofswitches, wherein the clip includes: a body part which is fixed to thecase; and elastic parts which extend from the body part and are forpressing the plurality of switches to the case, wherein the body partincludes a plurality of first through holes into which screws arecoupled, wherein the first through holes are disposed between twoadjacent elastic parts.

The body part may extend in a first direction, and the elastic parts mayextend in a second direction perpendicular to the first direction.

The clip may further include a support part, which extends from the bodypart and is bent to face a sidewall of the case.

The number of the first through holes may be a half of the number of theplurality of switches.

The case may include a stepped portion on which the body part isdisposed and which is screw-coupled.

The body part may include a first coupling groove and a second couplinggroove, which are formed on both ends of the body part in the firstdirection.

The case may include a first protrusion inserted into the first couplinggroove and a second protrusion inserted into the second coupling groove.

The power conversion device may further include: a cooling channeldisposed on the other surface of the case; and a coolant inlet and acoolant outlet, which are connected to the cooling channel.

The cooling channel may include a guide protrusion disposed inside thecooling channel.

The guide protrusion may extend from the coolant inlet to the coolantoutlet.

Advantageous Effects

According to embodiments, a plurality of switches can be fixed to a caseusing an uniform pressure. Thus, areas in which the plurality ofswitches contact a cooling system are uniform, which is advantageous forheat dissipation.

Various and useful advantages and effects of the present invention arenot limited to the above description and could be more easily understoodwhen specific embodiments of the present invention are described.

DESCRIPTION OF DRAWINGS

FIG. 1 is a view of a power conversion device according to an embodimentof the present invention.

FIG. 2 is a view of a cooling channel formed on a rear surface of a caseof FIG. 1.

FIG. 3 is a view of a clip for fixing a switching unit of FIG. 1.

FIG. 4 is a view of a state in which the switching unit is fixed by theclip.

FIG. 5 is a view for explaining positions of through holes of the clip.

FIG. 6 is a view for explaining positions at which elastic parts of theclip press switches.

FIG. 7 is a view for explaining a conventional clip.

FIG. 8 is a photo showing pressure distribution of switches fixed by theconventional clip.

MODES OF THE INVENTION

As the invention allows for various changes and numerous embodiments,particular embodiments will be illustrated in the drawings and describedin detail in the written description. However, this is not intended tolimit the present invention to particular modes of practice, and it isto be appreciated that all changes, equivalents, and substitutes that donot depart from the spirit and technical scope of the present inventionare encompassed in the present invention.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another. For example, a first element could be termed asecond element, and, similarly, a second element could be termed a firstelement, without departing from the scope of the present invention. Asused here, the term “and/or” includes any and all combinations of one ormore of the associated listed items.

It will be understood that when an element is referred to as being“connected” or “coupled” to another element, it can be directlyconnected or coupled to the other element or intervening elements may bepresent. In contrast, when an element is referred to as being “directlyconnected” or “directly coupled” to another element, there are nointervening elements present.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a,” “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises,”“comprising,” “includes” and/or “including,” when used herein, specifythe presence of stated features, integers, steps, operations, elements,components, and/or groups thereof but do not preclude the presence oraddition of one or more other features, integers, steps, operations,elements, components, and/or groups thereof.

In the description of embodiments, it will be understood that when anelement is referred to as being formed “on or under” another element,“on or under” means that two elements directly contact each other or oneor more other elements are disposed between the two elements and areindirectly formed. In addition, the case of an expression “on or under”may refer to both an upward direction and a downward direction based onone element.

Example embodiments of the invention will be described below in moredetail with reference to the accompanying drawings. Those componentsthat are the same or are corresponding are rendered the same referencenumerals regardless of the figure number, and redundant explanations areomitted.

FIG. 1 is a view of a power conversion device according to an embodimentof the present invention, and FIG. 2 is a view of a cooling channel ofFIG. 1.

Referring to FIGS. 1 and 2, the power conversion device according to anembodiment may include a case 10, a plurality of electronic components11 disposed on the case 10, a cover 20 coupled to one surface (i.e., afront or first side) of the case 10, and a cooling channel C for coolingthe case 10.

A direct current (DC)-DC converter that is a device for transforming aDC voltage may convert a DC into an alternating current (AC), maytransform and then rectify the current, thereby obtaining a DC. TheDC-DC converter may include a switching unit 11 including a plurality ofmetal oxide semiconductor field effect transistors (MOSFETs), atransformer T, an inductor, and a rectifying diode. The switching unit11 may be connected to a power terminal so as to switch a voltage, andthe transformer T may transform the voltage switched by the switchingunit 11.

Heat is generated in the DC-DC converter during an operation of theDC-DC converter. Thus, a cooling system is generally used to eliminateheat from the DC-DC converter. However, when an eddy occurs while ahigh-pressure coolant is circulated, or when the flow of a coolant isnot uniform, cooling efficiency is lowered.

Referring to FIG. 2, the cooling channel C may be disposed on onesurface (i.e., a bottom or second side) of the case 10. The coolingchannel C may include a first channel region 16 in which the coolant isintroduced and is circulated, and a second channel region 17 in whichthe coolant is circulated and then is discharged.

A coolant inlet 13 may be connected to the first channel region 16, anda coolant outlet 14 may be connected to the second channel region 17.The coolant inlet 13 and the coolant outlet 14 may be disposed inparallel on one side of the case 10. That is, the cooling channel C mayhave an U-shape.

The first channel region 16 and the second channel region 17 may bedivided by a divergence part 18 that extends from one side on which thecoolant inlet 13 is disposed, to the other side. That is, the firstchannel region 16 and the second channel region 17 may be symmetricalwith each other based on a virtual line P1 formed by extending thedivergence part 18. The divergence part 18 may have a width thatdecreases as it gets closer to the other side from one side thereof.

The first channel region 16 and the second channel region 17 may includea guide protrusion 15 that diverges the flow of the coolant. Both ends15 a and 15 b of the guide protrusion 15 may be bent as they get fartheraway from each other. The flow of the introduced coolant is improved byboth of the bent ends 15 a and 15 b so that an eddy can be preventedfrom being formed.

FIG. 3 is a view of a clip for fixing a switching unit of FIG. 1, FIG. 4is a view of a state in which the switching unit is fixed by the clip,FIG. 5 is a view for explaining positions of through holes of the clip,and FIG. 6 is a view for explaining positions at which elastic parts ofthe clip press switches.

Referring to FIGS. 3 and 4, a clip 100 according to an embodimentincludes a body part 110 fixed to the case 10, and elastic parts 120 forpressing a plurality of switches 11 a to the case 10.

The body part 110 includes a plurality of first through holes 111 andfirst and second coupling grooves 112 and 113. Screws 15 are coupledinto the first through holes 111, and the first through holes 111 arefixed to the case 10. The first and second coupling grooves 112 and 113may be formed in one end and the other end of the body part 110 in afirst direction. The body part 110 may extend in the first direction,and a width of the body part 110 in a second direction may be about 14mm or more. The first direction is an X-direction of the drawings, andthe second direction is a Y-direction of the drawings.

The plurality of elastic parts 120 extend from the body part 110 in thesecond direction. The elastic parts 120 may be bent to press theswitches 11 a (i.e., on the front or first side of the case 10) when thebody part 110 is fixed to the case 10. Each of the elastic parts 120 mayinclude a bending part 121 and a contact part 122. The shape of theelastic parts 120 is not specially limited.

A support part 114 may protrude in an opposite direction to the seconddirection and may be vertically bent. The support part 114 may bedisposed on a sidewall of the case 10, where the sidewall is between thefirst side and the second side of the case 10. When screw coupling isperformed by the support part 114, rotation of the clip 100 can beprevented.

Referring to FIG. 4, the body part 110 may extend to cover the pluralityof switches 11 a. Thus, each of the elastic parts 120 may extend fromthe body part 110 in the second direction and may press upper portionsof the switches 11 a, respectively.

The first and second coupling grooves 112 and 113 formed in both ends ofthe body part 110 are inserted into first and second protrusions 12 aand 12 b, respectively, which protrude from the case 10. The first andsecond protrusions 12 a and 12 b may be disposed on a stepped portion ofthe case. Thus, when the screws 15 are inserted into the first throughholes 111, rotation of the body part 110 can be prevented. The firstcoupling groove 112 may be a slit formed in a side surface of the bodypart 110.

When the body part 110 is disposed on the stepped portion of the case10, firstly, the first and second protrusions 12 a and 12 b are insertedinto the first and second coupling grooves 112 and 113, respectively, sothat the body part 110 can be disposed at its correct position.Subsequently, the screws 15 may be coupled into the first through holes111 and fixed thereto.

The number of first through holes 111 may be a half of the number of aplurality of switches 11 a. For example, when there are four switches 11a, the number of first through holes 111 may be two, and when there aresix switches 11 a, the number of first through holes 111 may be three.However, the number of first through holes and the number of switchesare not necessarily limited thereto.

A position of the first through holes 111 may be determined by a widthW₁ of each of the switches 11 a and a distance W₂ between the switches11 a. That is, the position of the first through holes 111 may be aposition at which there is a half ((2W₁+W₂)/2) of a value obtained byadding the width W₁ of two switches 11 a and the distance W₂ between theswitches 11 a.

Referring to FIG. 5, a distance W₃ between a central line L₂ of thefirst through holes 111 and an adjacent virtual straight line L₁ may beuniform. The virtual straight line L₁ is a virtual straight line inwhich the elastic parts 120 are divided by two in a longitudinaldirection.

Through this configuration, when the screws are coupled into the firstthrough holes 111, pressures generated by press of the adjacent elasticparts 120 may be almost the same. Thus, a bending phenomenon may bealleviated compared to a structure for screw-coupling both ends of thebody part (see FIG. 7).

Referring to FIG. 6, a point where the elastic parts 120 press theswitches 11 a, may be a center of the switches 11 a. A press optimumdistance W₇ may be the sum of a distance W₄ from an end to the center ofthe switches 11 a and a distance (W₅+W₆) from the end of the switches 11a to a center of the first through holes 111. Through thisconfiguration, the center of the switches 11 a may be pressed so thatoverall uniform areas of the switches 11 a can be in contact with thecase 10. The press optimum distance W₇ may be 15 mm to 25 mm, and adistance W₅ from the end of the switches 11 a to a stepped portion 115into which the screws are coupled, may be about 5.5 mm.

FIG. 7 is a view for explaining a conventional clip, and FIG. 8 is aphoto showing pressure distribution of switches fixed by theconventional clip.

Referring to FIGS. 7 and 8, when screws are coupled into holes 4 formedin both ends of the clip and the clip is fixed to a case, bendingoccurs. Thus, two plates 1 and 2 are required to be manufactured byoverlapping each other.

In addition, a press force of elastic parts 3 closer to the holes isrelatively increased so that contact areas P of a plurality of switchesmay be different from each other. Thus, a difference in cooling amongthe plurality of switches occurs so that performance of the powerconversion device may be deteriorated.

While the invention has been shown and described with reference tocertain exemplary embodiments thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the invention asdefined by the appended claims.

What is claimed is:
 1. A power conversion device comprising: a casecomprising a first protrusion and a second protrusion; a switching unitcomprising a plurality of switches disposed on one surface of the case;and a clip for fixing the plurality of switches; and wherein the clipcomprises: a body part which extends in a first direction; and elasticparts which extend from one side of the body part and are for pressingthe plurality of switches to the case, wherein the body part comprises:a plurality of first through holes, which are disposed in the firstdirection and into which screws are coupled; a first coupling groovedisposed on one end of the body part in the first direction; and asecond coupling groove disposed on the other end of the body part in thefirst direction, wherein the first protrusion is coupled to the firstcoupling groove and the second protrusion is coupled to the secondgroove, wherein the first coupling groove is longer than the secondcoupling groove in the first direction, and wherein the first throughholes are disposed between the first groove and the second groove. 2.The power conversion device of claim 1, wherein the case comprises astepped portion on which the body part is disposed, and a straight-linedistance from an end of the switches facing the stepped portion to thestepped portion is shorter than a straight-line distance from the end ofthe switches to a point where the elastic parts press the switches. 3.The power conversion device of claim 1, wherein the clip furthercomprises a support part, which extends from the body part and is bentto face a sidewall of the case.
 4. The power conversion device of claim1, wherein the number of the plurality of first through holes is a halfof the number of the plurality of switches.
 5. The power conversiondevice of claim 1, further comprising a transformer disposed on onesurface of the case, a cooling channel disposed on the other surface ofthe case, and a coolant inlet and a coolant outlet, which are connectedto the cooling channel, wherein the cooling channel comprises a firstchannel region connected to the coolant inlet and a second channelregion connected to the coolant outlet.
 6. The power conversion deviceof claim 5, wherein the cooling channel comprises a divergence partdisposed between the first channel region and the second channel region,and the divergence part has a width that decreases as it gets fartheraway from the coolant inlet and the coolant outlet.
 7. The powerconversion device of claim 5, wherein the cooling channel comprises aguide protrusion disposed inside the cooling channel.
 8. The powerconversion device of claim 7, wherein the guide protrusion extends fromthe coolant inlet to the coolant outlet.
 9. The power conversion deviceof claim 7, wherein the guide protrusion comprises a first end partfacing the coolant inlet and a second end part facing the coolantoutlet, and the first end part and the second end part are bent a